Raynaud's disease : Raynaud's disease is excessively reduced blood flow in response to cold or emotional stress, causing discoloration of the fingers, toes, and occasionally other areas. This condition may also cause nails to become brittle with longitudinal ridges. Named after French physician Maurice Raynaud (1834–1881), the phenomenon is believed to be the result of vasospasms that decrease blood supply to the respective regions.
Drug therapy options include Calcium channel blockers (nifedipine , amlodipine and felodipine), Alpha blockers( prazosin and doxazosin) and vasodilators(nitroglycerin, sildenafil).